Neighbor aware network cluster change for neighbor aware network data link

ABSTRACT

Aspects of the present disclosure provide techniques for synchronizing clocks in a Neighbor Aware Network (NAN) Data Link (NDL) cluster. An exemplary apparatus includes a processing system configured to communicate with one or more members of a group, that includes the apparatus, according to a first data communication window (DCW) timeline having a first offset relative to a first clock associated with a first network cluster, to detect a beacon transmitted by a device of a second network cluster, wherein the beacon comprises timing information of a second clock associated with the second network cluster, to determine whether to initiate a move of the group to the second network cluster, to generate a frame to initiate the move of the group to the second network cluster, the frame comprising a first indication of the timing information of the second clock, and an interface configured to output the frame for transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/266,768 entitled “NEIGHBOR AWARE NETWORK CLUSTER CHANGE FORNEIGHBOR AWARE NETWORK DATA LINK”, filed Sep. 15, 2016, which claimsbenefit of U.S. Provisional Application No. 62/221,597, filed Sep. 21,2015, each of which is assigned to the assignee of the presentapplication and hereby expressly incorporated by reference herein in itsentirety.

BACKGROUND Field of the Disclosure

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to time synchronization of datalinks in neighbor aware networks.

Description of Related Art

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

In order to address the desire for greater coverage and increasedcommunication range, various schemes are being developed. One suchscheme is the sub-1-GHz frequency range (e.g., operating in the 902-928MHz range in the United States) being developed by the Institute ofElectrical and Electronics Engineers (IEEE) 802.11ah task force. Thisdevelopment is driven by the desire to utilize a frequency range thathas greater wireless range than wireless ranges associated withfrequency ranges of other IEEE 802.11 technologies and potentially fewerissues associated with path losses due to obstructions.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications in a wireless network.

Aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, time synchronization of datalinks in neighbor aware networks (NANs).

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes a processing systemconfigured to communicate with one or more members of a group, thatincludes the apparatus, according to a first data communication window(DCW) timeline having a first offset relative to a first clockassociated with a first network cluster, to detect a beacon transmittedby a device of a second network cluster, wherein the beacon comprisestiming information of a second clock associated with the second networkcluster, to determine whether to initiate a move of the group to thesecond network cluster, to generate a frame to initiate the move of thegroup to the second network cluster, if the determination is to initiatethe move, the frame comprising the timing information of the secondclock, and an interface configured to output the frame for transmission.

Aspects of the present disclosure provide a method for wirelesscommunications performed by an apparatus. The method generally includescommunicating with members of a group, that includes the apparatus,according to a first data communication window (DCW) timeline having afirst offset relative to a first clock associated with a first networkcluster, detecting a beacon transmitted by a device of a second networkcluster, wherein the beacon comprises timing information of a secondclock associated with the second network cluster, determining whether toinitiate a move of the group to the second network cluster, generating aframe to initiate the move of the group to the second network cluster,if the determination is to initiate the move, the frame comprising afirst indication of the timing information of the second clock, andtransmitting the frame.

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes means for communicatingwith members of a group, that includes the apparatus, according to afirst data communication window (DCW) timeline having a first offsetrelative to a first clock associated with a first network cluster, meansfor detecting a beacon transmitted by a device of a second networkcluster, wherein the beacon comprises timing information of a secondclock associated with the second network cluster, means for determiningwhether to initiate a move of the group to the second network cluster,means for generating a frame to initiate the move of the group to thesecond network cluster, if the determination is to initiate the move,the frame comprising a first indication of the timing information of thesecond clock, and means for transmitting the frame.

Aspects of the present disclosure provide a computer program product.The computer program product generally includes a computer readablemedium storing instructions, the instructions when executed by aprocessing system cause an apparatus to communicate with members of agroup according to a first data communication window (DCW) timelinehaving a first offset relative to a first clock associated with a firstnetwork cluster, detect a beacon transmitted by a device of a secondnetwork cluster, wherein the beacon comprises timing information of asecond clock associated with the second network cluster, determinewhether to initiate a move of the group to the second network cluster,generate a frame to initiate the move of the group to the second networkcluster, if the determination is to initiate the move, the framecomprising a first indication of the timing information of the secondclock, and transmit the frame.

Aspects of the present disclosure provide a station. The stationgenerally includes at least one antenna, a transceiver, and a processingsystem configured to communicate, via the transceiver and the at leastone antenna, with members of a group, that includes the station,according to a first data communication window (DCW) timeline having afirst offset relative to a first clock associated with a first networkcluster, to detect, via the transceiver and the at least one antenna, abeacon associated with a second network cluster, wherein the beaconcomprises timing information of a second clock associated with thesecond network cluster, to determine whether to initiate a move of thegroup to the second network cluster, to generate a frame to initiate themove of the group to the second network cluster, if the determination isto initiate the move, the frame comprising a first indication of thetiming information of the second clock, and to transmit the frame viathe transceiver and the at least one antenna.

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes a receive interfaceconfigured to obtain a first frame announcing a move of a group ofdevices that includes the apparatus as a member, from a first networkcluster to a second network cluster, wherein the first frame comprisestiming information of a clock associated with the second network clusterand a processing system configured to determine, based on the timinginformation, a data communication window (DCW) timeline for theapparatus to communicate data with one or more members of the groupafter the move, and to communicate with the one or more members of thegroup after the move according to the DCW timeline.

Aspects of the present disclosure provide a method for wirelesscommunications performed by an apparatus. The method generally includesobtaining a first frame announcing a move of a group of devices thatincludes the apparatus as a member, from a first network cluster to asecond network cluster, wherein the first frame comprises timinginformation of a clock associated with the second network cluster,determining, based on the timing information, a data communicationwindow (DCW) timeline for the apparatus to communicate data with one ormore members of the group after the move, and communicating with the oneor more members of the group after the move according to the DCWtimeline.

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes means for obtaining afirst frame announcing a move of a group of devices that includes theapparatus as a member, from a first network cluster to a second networkcluster, wherein the first frame comprises timing information of a clockassociated with the second network cluster, means for determining, basedon the timing information, a data communication window (DCW) timelinefor the apparatus to communicate data with one or more members of thegroup after the move, and means for communicating with the one or moremembers of the group after the move according to the DCW timeline.

Aspects of the present disclosure provide a computer readable mediumstoring instructions, the instructions when executed by a processingsystem cause an apparatus to obtain a first frame announcing a move of agroup of devices that includes the apparatus as a member, from a firstnetwork cluster to a second network cluster, wherein the first framecomprises timing information of a clock associated with the secondnetwork cluster, to determine, based on the timing information, a datacommunication window (DCW) timeline for the apparatus to communicatedata with one or more members of the group after the move, and tocommunicate with the one or more members of the group after the moveaccording to the DCW timeline.

Aspects of the present disclosure provide a station. The stationgenerally includes at least one antenna, a transceiver, and a processingsystem configured to obtain, via the transceiver and the at least oneantenna, a first frame announcing a move of a group of devices thatincludes the apparatus as a member, from a first network cluster to asecond network cluster, wherein the first frame comprises timinginformation of a clock associated with the second network cluster, todetermine, based on the timing information, a data communication window(DCW) timeline for the apparatus to communicate data with one or moremembers of the group after the move, and to communicate, via thetransceiver and the at least one antenna, with the one or more membersof the group after the move according to the DCW timeline.

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes a receive interfaceconfigured to obtain a first frame announcing a move of a group ofdevices that includes the apparatus as a member, from a first networkcluster to a second network cluster, wherein the first frame comprisestiming information of a clock associated with the second network clusterand a processing system configured to determine, based on at least oneof services available in the first network cluster or activity of a datalink, to veto the move and to generate a second frame indicating thatthe apparatus vetoes the move, and a transmit interface configured tooutput the second frame for transmission to the first device.

Aspects of the present disclosure provide a method for wirelesscommunications performed by an apparatus. The method generally includesobtaining a first frame announcing a move of a group of devices thatincludes the apparatus as a member, from a first network cluster to asecond network cluster, wherein the first frame comprises timinginformation of a clock associated with the second network cluster,determining, based on at least one of services available in the firstnetwork cluster or activity of a data link, to veto the move, generatinga second frame indicating that the apparatus vetoes the move, andtransmitting the second frame to the first device.

Aspects of the present disclosure provide an apparatus for wirelesscommunications. The apparatus generally includes means for obtaining afirst frame announcing a move of a group of devices that includes theapparatus as a member, from a first network cluster to a second networkcluster, wherein the first frame comprises timing information of a clockassociated with the second network cluster, means for determining, basedon at least one of services available in the first network cluster oractivity of a data link, to veto the move, means for generating a secondframe indicating that the apparatus vetoes the move, and means fortransmitting the second frame to the first device.

Aspects of the present disclosure provide a computer readable mediumstoring instructions, the instructions when executed by a processingsystem cause an apparatus to obtain a first frame announcing a move of agroup of devices that includes the apparatus as a member, from a firstnetwork cluster to a second network cluster, wherein the first framecomprises timing information of a clock associated with the secondnetwork cluster, to determine, based on at least one of servicesavailable in the first network cluster or activity of a data link, toveto the move, to generate a second frame indicating that the apparatusvetoes the move, and to transmit the second frame to the first device.

Aspects of the present disclosure provide a station. The stationgenerally includes at least one antenna, a transceiver, and a processingsystem configured to obtain, via the transceiver and the at least oneantenna, a first frame announcing a move of a group of devices thatincludes the apparatus as a member, from a first network cluster to asecond network cluster, wherein the first frame comprises timinginformation of a clock associated with the second network cluster, todetermine, based on at least one of services available in the firstnetwork cluster or activity of a data link, to veto the move, togenerate a second frame indicating that the apparatus vetoes the move,and to communicate, via the transceiver and the at least one antenna,with the one or more members of the group after the move according tothe DCW timeline.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagram of an example wireless communicationsnetwork, in accordance with certain aspects of the present disclosure.

FIG. 2 illustrates a block diagram of an example access point and userterminals, in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates a block diagram of an example wireless device, inaccordance with certain aspects of the present disclosure.

FIG. 4 illustrates an example NAN cluster, in accordance with certainaspects of the present disclosure.

FIG. 5 illustrates an example NAN network with overlapping NAN clusters,in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates an example NAN network with a plurality of NAN DataLink (NDL) clusters, in accordance with certain aspects of the presentdisclosure.

FIG. 7 is an example time sequence diagram illustrating an exampletimeline of NAN discovery window periods and NDL time blocks, inaccordance with certain aspects of the present disclosure.

FIG. 8 illustrates an exemplary NAN network, according to aspects of thepresent disclosure.

FIG. 9 illustrates a block diagram of example operations for wirelesscommunications by an apparatus, in accordance with certain aspects ofthe present disclosure.

FIG. 9A illustrates example means capable of performing the operationsshown in FIG. 9.

FIG. 10 illustrates a block diagram of example operations for wirelesscommunications by an apparatus, in accordance with certain aspects ofthe present disclosure.

FIG. 10A illustrates example means capable of performing the operationsshown in FIG. 10.

FIG. 11 illustrates a block diagram of example operations for wirelesscommunications by an apparatus, in accordance with certain aspects ofthe present disclosure.

FIG. 11A illustrates example means capable of performing the operationsshown in FIG. 11.

FIG. 12 illustrates a set of example communications timelines, inaccordance with aspects of the present disclosure.

FIG. 13 illustrates a set of example communications timelines, inaccordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

Aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, numerology and frames forneighbor aware networks (NAN) in the sub-1GHz (S1G) band. As will bedescribed in more detail herein, different types of discovery windows(DWs) of different durations and at different intervals may be defined.A NAN device (e.g., access point (AP) or non-AP station in the NAN) maywake up during one or more types of discovery windows to transmit timesynchronization information and/or service discovery information.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Thedetailed description and drawings are merely illustrative of thedisclosure rather than limiting, the scope of the disclosure beingdefined by the appended claims and equivalents thereof.

The techniques described herein may be used for various broadbandwireless communication systems, including communication systems that arebased on an orthogonal multiplexing scheme. Examples of suchcommunication systems include Spatial Division Multiple Access (SDMA)system, Time Division Multiple Access (TDMA) system, OrthogonalFrequency Division Multiple Access (OFDMA) system, and Single-CarrierFrequency Division Multiple Access (SC-FDMA) system. An SDMA system mayutilize sufficiently different directions to simultaneously transmitdata belonging to multiple user terminals. A TDMA system may allowmultiple user terminals to share the same frequency channel by dividingthe transmission signal into different time slots, each time slot beingassigned to different user terminal. An OFDMA system utilizes orthogonalfrequency division multiplexing (OFDM), which is a modulation techniquethat partitions the overall system bandwidth into multiple orthogonalsub-carriers. These sub-carriers may also be called tones, bins, etc.With OFDM, each sub-carrier may be independently modulated with data. AnSC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit onsub-carriers that are distributed across the system bandwidth, localizedFDMA (LFDMA) to transmit on a block of adjacent sub-carriers, orenhanced FDMA (EFDMA) to transmit on multiple blocks of adjacentsub-carriers. In general, modulation symbols are sent in the frequencydomain with OFDM and in the time domain with SC-FDMA.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g.,nodes). In some aspects, a wireless node implemented in accordance withthe teachings herein may comprise an access point or an access terminal.

An access point (“AP”) may comprise, be implemented as, or known as aNode B, Radio Network Controller (“RNC”), evolved Node B (eNB), BaseStation Controller (“BSC”), Base Transceiver Station (“BTS”), BaseStation (“BS”), Transceiver Function (“TF”), Radio Router, RadioTransceiver, Basic Service Set (“BSS”), Extended Service Set (“ESS”),Radio Base Station (“RBS”), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or known as asubscriber station, a subscriber unit, a mobile station (MS), a remotestation, a remote terminal, a user terminal (UT), a user agent, a userdevice, user equipment (UE), a user station, or some other terminology.In some implementations, an access terminal may comprise a cellulartelephone, a cordless telephone, a Session Initiation Protocol (“SIP”)phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, a Station (“STA” such as an “AP STA” acting as an AP or a“non-AP STA”) or some other suitable processing device connected to awireless modem. Accordingly, one or more aspects taught herein may beincorporated into a phone (e.g., a cellular phone or smart phone), acomputer (e.g., a laptop), a tablet, a portable communication device, aportable computing device (e.g., a personal data assistant), anentertainment device (e.g., a music or video device, or a satelliteradio), a global positioning system (GPS) device, or any other suitabledevice that is configured to communicate via a wireless or wired medium.In some aspects, the AT may be a wireless node. Such wireless node mayprovide, for example, connectivity for or to a network (e.g., a widearea network such as the Internet or a cellular network) via a wired orwireless communication link.

An Example Wireless Communications System

FIG. 1 illustrates a system 100 in which aspects of the disclosure maybe performed. For example, any of the wireless stations including theaccess point 110 and/or the user terminals 120 may be in a neighboraware network (NAN). A wireless station may wake up during a first typeof discovery window having a first duration and occurring at a firstinterval and send and/or monitor for time synchronization information orservice information.

A wireless station may wake up during one or more types of discoverywindows to transmit time synchronization information and/or servicediscovery information. Different types of discovery windows of differentdurations and at different intervals may be defined.

The system 100 may be, for example, a multiple-access multiple-inputmultiple-output (MIMO) system 100 with access points and user terminals.For simplicity, only one access point 110 is shown in FIG. 1. An accesspoint is generally a fixed station that communicates with the userterminals and may also be referred to as a base station or some otherterminology. A user terminal may be fixed or mobile and may also bereferred to as a mobile station, a wireless device, or some otherterminology. Access point 110 may communicate with one or more userterminals 120 at any given moment on the downlink and uplink. Thedownlink (i.e., forward link) is the communication link from the accesspoint to the user terminals, and the uplink (i.e., reverse link) is thecommunication link from the user terminals to the access point. A userterminal may also communicate peer-to-peer with another user terminal.

A system controller 130 may provide coordination and control for theseAPs and/or other systems. The APs may be managed by the systemcontroller 130, for example, which may handle adjustments to radiofrequency power, channels, authentication, and security. The systemcontroller 130 may communicate with the APs via a backhaul. The APs mayalso communicate with one another, e.g., directly or indirectly via awireless or wireline backhaul.

While portions of the following disclosure will describe user terminals120 capable of communicating via Spatial Division Multiple Access(SDMA), for certain aspects, the user terminals 120 may also includesome user terminals that do not support SDMA. Thus, for such aspects, anAP 110 may be configured to communicate with both SDMA and non-SDMA userterminals. This approach may conveniently allow older versions of userterminals (“legacy” stations) to remain deployed in an enterprise,extending their useful lifetime, while allowing newer SDMA userterminals to be introduced as deemed appropriate.

The system 100 employs multiple transmit and multiple receive antennasfor data transmission on the downlink and uplink. The access point 110is equipped with N_(ap) antennas and represents the multiple-input (MI)for downlink transmissions and the multiple-output (MO) for uplinktransmissions. A set of K selected user terminals 120 collectivelyrepresents the multiple-output for downlink transmissions and themultiple-input for uplink transmissions. For pure SDMA, it is desired tohave N_(ap)≧K≧1 if the data symbol streams for the K user terminals arenot multiplexed in code, frequency or time by some means. K may begreater than N_(ap) if the data symbol streams can be multiplexed usingTDMA technique, different code channels with CDMA, disjoint sets ofsubbands with OFDM, and so on. Each selected user terminal transmitsuser-specific data to and/or receives user-specific data from the accesspoint. In general, each selected user terminal may be equipped with oneor multiple antennas (i.e., N_(ut)≧1). The K selected user terminals canhave the same or different number of antennas.

The system 100 may be a time division duplex (TDD) system or a frequencydivision duplex (FDD) system. For a TDD system, the downlink and uplinkshare the same frequency band. For an FDD system, the downlink anduplink use different frequency bands. MIMO system 100 may also utilize asingle carrier or multiple carriers for transmission. Each user terminalmay be equipped with a single antenna (e.g., in order to keep costsdown) or multiple antennas (e.g., where the additional cost can besupported). The system 100 may also be a TDMA system if the userterminals 120 share the same frequency channel by dividingtransmission/reception into different time slots, each time slot beingassigned to different user terminal 120.

FIG. 2 illustrates example components of the AP 110 and two UTs 120 mand 120 x, which are examples of the UTs 120 operating in the MIMOsystem 100 illustrated in FIG. 1. One or more components of the AP 110and UT 120 may be used to practice aspects of the present disclosure.For example, antenna 224, Tx/Rx 222, processors 210, 220, 240, 242,and/or controller 230 or antenna 252, Tx/Rx 254, processors 260, 270,288, and 290, and/or controller 280 may be used to perform theoperations described herein and illustrated with reference to FIGS. 10and 10.

The access point 110 is equipped with N_(t) antennas 224 a through 224ap. User terminal 120 m is equipped with N_(ut,m) antennas 252 mathrough 252 mu, and user terminal 120 x is equipped with N_(ut,x)antennas 252 xa through 252 xu. The access point 110 is a transmittingentity for the downlink and a receiving entity for the uplink. Each userterminal 120 is a transmitting entity for the uplink and a receivingentity for the downlink. As used herein, a “transmitting entity” is anindependently operated apparatus or device capable of transmitting datavia a wireless channel, and a “receiving entity” is an independentlyoperated apparatus or device capable of receiving data via a wirelesschannel. In the following description, the subscript “dn” denotes thedownlink, the subscript “up” denotes the uplink, N_(up) user terminalsare selected for simultaneous transmission on the uplink, N_(dn) userterminals are selected for simultaneous transmission on the downlink,N_(up) may or may not be equal to N_(dn), and N_(up) and N_(dn) may bestatic values or can change for each scheduling interval. Thebeam-steering or some other spatial processing technique may be used atthe access point and user terminal.

On the uplink, at each user terminal 120 selected for uplinktransmission, a transmit (TX) data processor 288 receives traffic datafrom a data source 286 and control data from a controller 280. Thecontroller 280 may be coupled with a memory 282. TX data processor 288processes (e.g., encodes, interleaves, and modulates) the traffic datafor the user terminal based on the coding and modulation schemesassociated with the rate selected for the user terminal and provides adata symbol stream. A TX spatial processor 290 performs spatialprocessing on the data symbol stream and provides N_(ut,m) transmitsymbol streams for the N_(ut,m) antennas. Each transmitter unit (TMTR)254 receives and processes (e.g., converts to analog, amplifies,filters, and frequency upconverts) a respective transmit symbol streamto generate an uplink signal. N_(ut,m) transmitter units 254 provideN_(ut,m) uplink signals for transmission from N_(ut,m) antennas 252 tothe access point.

N_(up) user terminals may be scheduled for simultaneous transmission onthe uplink. Each of these user terminals performs spatial processing onits data symbol stream and transmits its set of transmit symbol streamson the uplink to the access point.

At access point 110, N_(ap) antennas 224 a through 224 ap receive theuplink signals from all N_(up) user terminals transmitting on theuplink. Each antenna 224 provides a received signal to a respectivereceiver unit (RCVR) 222. Each receiver unit 222 performs processingcomplementary to that performed by transmitter unit 254 and provides areceived symbol stream. An RX spatial processor 240 performs receiverspatial processing on the N_(ap) received symbol streams from N_(ap)receiver units 222 and provides N_(up) recovered uplink data symbolstreams. The receiver spatial processing is performed in accordance withthe channel correlation matrix inversion (CCMI), minimum mean squareerror (MMSE), soft interference cancellation (SIC), or some othertechnique. Each recovered uplink data symbol stream is an estimate of adata symbol stream transmitted by a respective user terminal. An RX dataprocessor 242 processes (e.g., demodulates, deinterleaves, and decodes)each recovered uplink data symbol stream in accordance with the rateused for that stream to obtain decoded data. The decoded data for eachuser terminal may be provided to a data sink 244 for storage and/or acontroller 230 for further processing. The controller 230 may be coupledwith a memory 232.

On the downlink, at access point 110, a TX data processor 210 receivestraffic data from a data source 208 for N_(dn) user terminals scheduledfor downlink transmission, control data from a controller 230, andpossibly other data from a scheduler 234. The various types of data maybe sent on different transport channels. TX data processor 210 processes(e.g., encodes, interleaves, and modulates) the traffic data for eachuser terminal based on the rate selected for that user terminal. TX dataprocessor 210 provides N_(dn) downlink data symbol streams for theN_(dn) user terminals. A TX spatial processor 220 performs spatialprocessing (such as a precoding or beamforming, as described in thepresent disclosure) on the N_(dn) downlink data symbol streams, andprovides N_(ap) transmit symbol streams for the N_(ap) antennas. Eachtransmitter unit 222 receives and processes a respective transmit symbolstream to generate a downlink signal. N_(ap) transmitter units 222providing N_(ap) downlink signals for transmission from N_(ap) antennas224 to the user terminals. The decoded data for each user terminal maybe provided to a data sink 272 for storage and/or a controller 280 forfurther processing.

At each user terminal 120, N_(ut,m) antennas 252 receive the N_(ap)downlink signals from access point 110. Each receiver unit 254 processesa received signal from an associated antenna 252 and provides a receivedsymbol stream. An RX spatial processor 260 performs receiver spatialprocessing on N_(ut,m) received symbol streams from N_(ut,m) receiverunits 254 and provides a recovered downlink data symbol stream for theuser terminal. The receiver spatial processing is performed inaccordance with the CCMI, MMSE or some other technique. An RX dataprocessor 270 processes (e.g., demodulates, deinterleaves and decodes)the recovered downlink data symbol stream to obtain decoded data for theuser terminal.

At each user terminal 120, a channel estimator 278 estimates thedownlink channel response and provides downlink channel estimates, whichmay include channel gain estimates, SNR estimates, noise variance and soon. Similarly, at access point 110, a channel estimator 228 estimatesthe uplink channel response and provides uplink channel estimates.Controller 280 for each user terminal typically derives the spatialfilter matrix for the user terminal based on the downlink channelresponse matrix H_(dn,m) for that user terminal. Controller 230 derivesthe spatial filter matrix for the access point based on the effectiveuplink channel response matrix H_(up,eff). Controller 280 for each userterminal may send feedback information (e.g., the downlink and/or uplinkeigenvectors, eigenvalues, SNR estimates, and so on) to the accesspoint. Controllers 230 and 280 also control the operation of variousprocessing units at access point 110 and user terminal 120,respectively.

FIG. 3 illustrates various components that may be utilized in a wirelessdevice 302 that may be employed within the MIMO system 100. The wirelessdevice 302 is an example of a device that may be configured to implementthe various methods described herein. For example, the wireless devicemay implement operations 1000 and 1100 illustrated in FIGS. 9 and 11.The wireless device 302 may be an access point 110 or a user terminal120.

The wireless device 302 may include a processor 304 which controlsoperation of the wireless device 302. The processor 304 may also bereferred to as a central processing unit (CPU). Memory 306, which mayinclude both read-only memory (ROM) and random access memory (RAM),provides instructions and data to the processor 304. A portion of thememory 306 may also include non-volatile random access memory (NVRAM).The processor 304 typically performs logical and arithmetic operationsbased on program instructions stored within the memory 306. Theinstructions in the memory 306 may be executable to implement themethods described herein.

The wireless device 302 may also include a housing 308 that may includea transmitter 310 and a receiver 312 to allow transmission and receptionof data between the wireless device 302 and a remote node. Thetransmitter 310 and receiver 312 may be combined into a transceiver 314.A single or a plurality of transmit antennas 316 may be attached to thehousing 308 and electrically coupled to the transceiver 314. Thewireless device 302 may also include (not shown) multiple transmitters,multiple receivers, and multiple transceivers.

The wireless device 302 may also include a signal detector 318 that maybe used in an effort to detect and quantify the level of signalsreceived by the transceiver 314. The signal detector 318 may detect suchsignals as total energy, energy per subcarrier per symbol, powerspectral density and other signals. The wireless device 302 may alsoinclude a digital signal processor (DSP) 320 for use in processingsignals.

The various components of the wireless device 302 may be coupledtogether by a bus system 322, which may include a power bus, a controlsignal bus, and a status signal bus in addition to a data bus.

Example Neighbor Aware Network

Due to the increasing popularity of location-enabled (e.g., GPS-enabled)mobile devices, neighbor aware networks (NANs) are emerging. A NAN mayrefer to a network for communication between stations (STAs) that arelocated in close proximity to each other. Neighbor aware networking(NAN) provides a mechanism for devices to synchronize the time andchannel on which the devices converge to facilitate the discovery ofservices that have been made discoverable on the existing devices in aNAN or new devices that enter the environment,

A WiFi capable capable of communicating according to one or more IEEE802.11 standards) device that supports NAN protocols and that may be aNAN Master or a NAN non-Master may be referred to as a NAN device.

A NAN discovery window may refer to the time and channel on which NANdevices converge. That is, devices in a NAN may converge on a set oftime and frequency resources for exchanging (e.g., transmittiniz,receiving) information regarding the NAN, referred to as a NAN discoverywindow. A collection of NAN devices that are synchronized to a samediscovery window schedule may be referred to as a NAN cluster.

FIG. 4 illustrates an example NAN cluster 400, in accordance withcertain aspects of the present disclosure. NAN Devices (e.g., such as AP110 or user terminal 120) 410, 412, 414, 416 that are part of the sameNAN Cluster participate in a NAN Master Selection procedure. Dependingon changes in the NAN Cluster, such as NAN Devices becoming part of orleaving the NAN Cluster and Master Ranks of those NAN devices, differentNAN Devices may be elected to become NAN Devices in Master role for theNAN cluster at different times.

A NAN ID may be used to signify a set of NAN parameters e.g., discoverychannels, discover window times). A NAN network may refer to acollection of NAN clusters that share a same NAN ID.

FIG. 5 illustrates an example NAN network 500 with overlapping NANclusters 502, 504, in accordance with certain aspects of the presentdisclosure. Although not shown in FIG. 5, a NAN device may participatein more than one overlapping cluster. Also not shown, a NAN device mayoperate concurrently in a NAN network with other types of WiFi networks(e.g., STAs in different homes or buildings as pan of independent LANswith different external network connections), such as a wireless localarea network (WLAN) or WiFi Direct.

NANs generally utilize a discovery window to advertise the existence ofdevices, services offered by the NAN, and synchronization information.During the discovery window, NAN Devices of the NAN are available (e.g.,the NAN devices power on receiver components to listen for transmissionsand make themselves available) with high probability for mutualdiscovery. During interim periods, the devices may be asleep (e.g., in alow power mode with one or more receiver components powered down) orinvolved with other activities, for example, communicating on othernetworks and/or a different channel. A NAN device that creates the NANcluster may define a series of discovery window start times (DWSTs) fordiscovery windows of the NAN cluster, described below.

NAN Devices participating in the same NAN Cluster are synchronized to acommon clock. During a discovery window, one or more NAN Devicestransmit NAN Synchronization Beacon frames (also referred to as NANbeacon frames and NAN beacons) to help all NAN Devices within the NANCluster synchronize their clocks. A timing synchronization function(TSF) keeps the timers of all NAN Devices in the same NAN Clustersynchronized. The TSF in a NAN Cluster may be implemented via adistributed algorithm, and NAN beacon frames can be transmitted (e.g.,by one or more NAN devices in the cluster) according to the algorithmdescribed. A relative starting point or “time zero” may be defined asthe first DWST. According to certain aspects, all devices in the NAN maywake up at the first discovery window (DWO), which may be defined, forexample, as the discovery window in which the lower 23 bits of a valueof the TSF are zero. During subsequent discovery windows, certain NANdevices may choose to be awake (e.g., wake up if in a power save mode)or not be awake (e.g., enter or remain in a power save mode).Synchronization may decrease the discovery latency of devices, powerconsumption by devices, and medium occupancy by devices that wouldotherwise occur.

The NAN synchronization procedure is separate from service discoverymessaging. Although a NAN Device transmits not more than oneSynchronization Beacon in a discovery window, multiple NAN ServiceDiscovery frames may be transmitted by a NAN Device in a discoverywindow. NAN Service Discovery frames make services discoverable by otherNAN Devices, possibly enabling NAN Devices to look for services fromother NAN Devices.

Each device within a NAN may have an anchor master rank. The anchormaster rank may indicate, for example, the relative accuracy of a clockassociated with the device. Devices within a NAN may synchronize clockswith the device in the NAN having a highest anchor master rank (e.g.,the device indicated as having the most accurate clock).

In some cases, as illustrated in FIG. 6, a NAN data link (NDL) cluster602, 604 may be formed from a plurality of devices that are members ofat least one NAN cluster 610, 612. An NDL cluster may comprise membersof a single NAN cluster, as illustrated by NDL cluster 602, or membersof multiple NAN clusters, as illustrated by NDL cluster 604. A member ofan NDL cluster may perform data communications within the NDL cluster,but not necessarily with other members of the NAN to which the memberbelongs. Devices within an NDL cluster may perform communications withinthe NDL cluster outside of a NAN discovery window and not concurrentlywith transmissions within the NAN.

FIG. 7 illustrates an example timeline 700 of communications within aNAN cluster and an NDL cluster. As illustrated, on the NAN discoverychannel 702, DWSTs 708 have an interval of 512 time units (TUs) (i.e.,the beginning of a discovery window is 512 TUs after the beginning of aprevious discovery window). NDL Time Blocks 706, in which communicationssuch as those shown on channel A 704 may be performed within the NDLcluster, may be offset in time from the DWST. In some cases, NDL TimeBlock times may be set at fixed offsets, relative to the discoverywindow timeline. That is, each NDL Time Block time may begin a fixedoffset from a corresponding DWST. NDL Time Block times may occuraccording to an NDL base schedule. Devices within an NDL cluster mayreceive information regarding the NDL base schedule from other deviceswithin the NDL cluster, and may negotiate the NDL base schedule with theother devices.

When a NAN Data Link (NDL) cluster is initialized, an NDL timeline maybe determined based on the discovery window timeline of the originatingcluster (e.g., the originating NAN cluster). Once the NDL cluster isinitialized, the NDL cluster may maintain a timeline that is independentof a discovery window timeline. The NDL timeline may not shift, even asthe originating NAN cluster changes. If all devices in the NDL clusterare members of the same NAN cluster, the NDL clock may be synchronizedwith the NAN clock.

In a dynamic environment, changes in a NAN cluster with which a memberof an NDL cluster is associated may in turn cause a shift in a discoverywindow timeline of the NAN cluster. If, for example, NDL Time Blocktimes are set as a fixed offset from DWSTs as mentioned above, the NDLmay fail due to cluster timing changes causing different devices in theNDL cluster to calculate different NDL Time Block times. Since thedevices in the NDL cluster may calculate different NDL Time Block times,data transmission in the NDL may be misaligned, causing datacommunication failures between some devices in the NDL cluster. Thus,techniques for synchronizing timing within an NDL cluster may bedesirable.

Example Neighbor Aware Network Cluster Change for Neighbor Aware NetworkData Link

According to certain aspects of the present disclosure, for NAN DataLink (NDL) clusters, an NDL timeline may be determined based on adiscovery window timeline of an originating NAN cluster. That is,devices in a NAN cluster may form an NDL cluster with an NDL timelinebased on the discovery window timeline of the NAN cluster. As describedabove, when a device that is a member of an NDL detects another NANcluster and determines to join the other NAN cluster, the NDL may faildue to changes in cluster timing caused by the device joining the otherNAN cluster. The device may determine to join the other NAN clusterbased on an anchor master rank of an anchor master of the other cluster,how many times and how often the device has detected the other cluster,and/or services offered in the other cluster.

A device that is a member of an NDL and determines to join a new NANcluster may communicate information regarding the new NAN cluster toanother member (e.g., another device) of the NDL so that the two devicesmay move to the new NAN cluster (e.g., port the NDL to a new timelinethat is based on timing information, such as a time synchronizationfunction (TSF), of the new NAN cluster). The two devices may continue tocommunicate via the NDL after moving to the new timeline.

FIG. 8 illustrates an exemplary NAN network 800 in which aspects of thepresent disclosure may be practiced. There are two NAN clusters 802,830, referred to as NAN1 and NAN2. In the exemplary NAN network, NANcluster 802 originally includes the nodes represented as circles, whileNAN cluster 830 originally includes the nodes represented as squares.Nodes (e.g., stations) 808, 812, 814, and 816 have formed a NAN datalink cluster 804 within NAN cluster 802 (NAN1). While the NAN data linkcluster is shown with four nodes, aspects of the present disclosure maybe practiced in NAN data link clusters with more or fewer nodes. Asillustrated, the NAN cluster 802 has an anchor master node 806 that isnot a member of the NAN data link cluster 804 with 808, 812, 814, and816. Also as illustrated, the NAN cluster 802 may also have a number ofother nodes, although aspects of the present disclosure may be practicedwithout the other nodes. The second NAN cluster 830 has an anchor masternode 832.

According to aspects of the present disclosure, a first node, e.g. node812, may be a member of a first NAN cluster (e.g., NAN1 802) and mayhave one or more NDLs with other nodes (e.g., nodes 808, 814, 816),forming a NAN data link cluster (NDC), e.g., NDC 804. The first node maydetect an anchor beacon from a second NAN cluster (e.g., NAN 830). Thefirst node may determine to join the second NAN cluster based on ananchor master rank of an anchor master of the second NAN cluster, howmany times and how often the device has detected the second NAN cluster,and/or services offered in the second NAN cluster. For example, if theanchor master rank of the anchor master node 832 is higher than ananchor master rank of anchor master node 806, then node 812 maydetermine to join the second NAN cluster. In a second example, the node812 may detect the anchor beacon 834 a first time and determine not tojoin the second NAN cluster, as the second NAN cluster may be a passingNAN cluster. Continuing the second example, the node 812 may detect asecond anchor beacon from anchor master node 832 at a later time anddetermine to join the second NAN cluster, as the second NAN cluster doesnot appear to be passing by. In a third example, the node 812 may detectthe anchor beacon 834, determine that a desired service (e.g., a gameservice) is offered in the second NAN cluster, and determine to join thesecond NAN cluster, because the desired service is offered in the secondNAN cluster.

Upon determining to join the second NAN cluster, the first node maytransmit a beacon or cluster transition message 810, in the NAN datalink base schedule of the NAN data link cluster, announcing the secondNAN cluster to one or more other nodes, e.g., nodes that are in the NANdata link cluster with the first node (e.g., nodes 808, 814, 816). Thefirst node may negotiate, with other nodes receiving the beacon orcluster transition message, times to transition NDLs between each pairof nodes to port the NDLs to a new timeline based on timing information(e.g., a TSF) of the second NAN cluster. A node (e.g., node 808)receiving a beacon or cluster transition message announcing another NANcluster may also transmit a message announcing the other NAN cluster toother nodes and negotiate one or more times to transition each NDLbetween the node transmitting the message and each receiving node. Forexample and with reference to FIG. 8, node 812 is a member of NAN 802when node 812 detects an anchor beacon 834 from the anchor master 832 ofNAN 830. In the example, node 812 determines to transition to NAN 830and sends a cluster transition message or beacon 810, in the NAN datalink base schedule of NDC 804, announcing that node 812 will transitionto NAN 830. Still in the example, node 812 and node 814 negotiate a timeto transition the NDL 822 between node 812 and node 814 to use timinginformation from NAN 830. Also in the example, node 808 receives themessage announcing the transition of node 812 to NAN 830, and node 808negotiates with node 816, via one or more messages 820, to determine atime to transition the NDL 824 between node 808 and node 816 to usetiming information from NAN 830.

FIG. 9 illustrates example operations 900 that may be performed by anapparatus (e.g., a station) to update an NDL when moving from a firstnetwork cluster to a second network cluster as described above,according to aspects of the present disclosure.

Operations 900 begin at 902, where the apparatus communicates with oneor more members of a group that includes the apparatus, according to afirst data communication window (DCW) timeline (e.g., a NAN data linkbase schedule), having a first offset relative to a first clockassociated with a first network cluster. For example and with referenceto FIG. 8, an apparatus included in node 812 communicates with node 814according to a NAN data link base schedule of the NAN data link cluster804.

At 904, the apparatus detects a beacon associated with a second networkcluster, wherein the beacon comprises timing information of a secondclock associated with the second network cluster. Continuing the exampleabove, the apparatus included in node 812 detects the anchor beacon 834,which is transmitted by node 832 and has timing information of the NANcluster 830.

At 906, the apparatus determines whether to initiate a move of the groupto the second network cluster. Continuing the example above, theapparatus included in node 812 determines to initiate a move of the NANdata link cluster 804 to NAN cluster 830.

At 908, the apparatus generates a frame to initiate the move of thegroup to the second network cluster, if the determination is to initiatethe move, the frame comprising a first indication of the timinginformation of the second clock. Continuing the example above, theapparatus included in node 812 generates a frame including a beacon orcluster transition message 810, which has an indication of the timinginformation of the NAN cluster 830.

At 910, the apparatus outputs the frame for transmission. Continuing theexample above, the apparatus included in node 812 outputs fortransmission the frame including the beacon or cluster transitionmessage 810.

According to aspects of the present disclosure, a station (e.g., adevice, a node) that is a member of a first NAN cluster and participatesin a NAN data link cluster may discover a second NAN cluster. Thestation may discover the second NAN cluster by, for example, receivingan anchor beacon transmitted by an anchor master of the second NANcluster. Such a station may transmit a beacon or cluster transitionmessage with information about the second cluster in the NDL baseschedule (e.g., during one or more DCWs of a DCW timeline) of the NDLcluster. The information that the station includes in the beacon orcluster transition message may include a TSF of the second cluster, ananchor master rank (AMR) of the second cluster, and a time that thestation is moving (e.g., transitioning) to a schedule based on thesecond cluster. The anchor master rank may represent a grade, to operateas an anchor master, of a device operating as an anchor master of thesecond cluster. As used herein, the term grade may generally refer to acredential or rank, for example, that allows a device to provide certainservices including, but not limited to, operating as an anchor master. Astation moving to a second NAN cluster that is participating in an NDLwith another device may receive confirmation of a new NDL schedule(e.g., a data communication window timeline) from the other device inresponse to the beacon or cluster transition message.

According to aspects of the present disclosure, a station that is amember of a first NAN cluster, participates in a NAN data link cluster,and discovers a second NAN cluster may determine to initiate a move ofthe NAN data link cluster based on an anchor master rank of an anchormaster of the second NAN cluster. For example and with reference to FIG.8, node 812 may determine to join the second NAN cluster 830, if theanchor master rank of the anchor master node 832 is higher than ananchor master rank of anchor master node 806.

According to aspects of the present disclosure, a station that is amember of a first NAN cluster, participates in a NAN data link cluster,and discovers a second NAN cluster may determine to initiate a move ofthe NAN data link cluster based on how many times and how often thestation has detected the second NAN cluster. The station may determine(e.g., based on a wireless communications standard) a threshold numberof times the station should detect a beacon from the second NAN clusterbefore initiating a move of the NAN data link cluster to the second NANcluster to prevent the station from initiating moves to clusters thatare passing by. For example and with reference to FIG. 8, the node 812may determine a threshold of two times of detecting a second networkcluster before initiating moves to the second network cluster (e.g., thenode should detect a beacon from the second network cluster twice). Inthe example, the node 812 may detect the anchor beacon 834 a first timeand determine not to join the second NAN cluster 830, as the node hasnot detected the second network cluster the threshold number of times.Continuing the example, the node 812 may detect a second anchor beaconfrom anchor master node 832 at a later time and determine to join thesecond NAN cluster, as the node has detected the second network clusterthe threshold number of times.

According to aspects of the present disclosure, a station that is amember of a first NAN cluster, participates in a NAN data link cluster,and discovers a second NAN cluster may determine to initiate a move ofthe NAN data link cluster based on services offered in the second NANcluster. For example and with reference to FIG. 8, the node 812 maydetect the anchor beacon 834, determine that a desired service (e.g., agame service) is offered in the second NAN cluster, and determine tojoin the second NAN cluster, because the desired service is offered inthe second NAN cluster.

According to aspects of the present disclosure, a station moving from afirst NAN cluster to a second NAN cluster may compute a time for themove based on estimates of how quickly other devices (e.g., devicesparticipating in an NDL with the station) will be able to transition toa new NDL timeline (e.g., a data communication window timeline).

According to aspects of the present disclosure, a station in a first NANcluster participating in a first NDL may use a first NDL schedule (e.g.,a DCW timeline) based on a sequence (e.g., a base sequence) of DCWsbeginning at the first offset relative to a discovery window associatedwith the first NAN cluster. The offset may be determined as a number ofTUs or slots. The station may determine to move to a second NAN clusterand may determine a second NDL schedule to be used in the NDL aftermoving to the second NAN cluster. Such a station may determine to use asecond NDL schedule that is based on the same (base) sequence of DCWsbeginning at the first offset relative to a discovery window associatedwith the second NAN cluster.

According to aspects of the present disclosure, a station participatingin an NDL and moving from a first NAN cluster to a second NAN clustermay include a time for the NDL cluster to transition to the second NANcluster in a beacon or cluster transition message initiating a move ofthe NDL cluster to the second NAN cluster.

According to aspects of the present disclosure, timing informationincluded in a beacon or cluster transition message initiating a movefrom a first NAN cluster to a second NAN cluster may include a timingsynchronization function (TSF) value of the second NAN cluster.According to some aspects of the present disclosure, timing informationincluded in the beacon or cluster transition message initiating the movefrom the first NAN cluster to the second NAN cluster may include anoffset of a TSF of the second NAN cluster relative to a TSF of the firstNAN cluster. When a station indicates the offset of the TSF of thesecond NAN cluster relative to the TSF of the first NAN cluster in thebeacon or cluster transition message initiating the move to the secondNAN cluster, then a device receiving the beacon or cluster transitionmessage may use the offset of the TSF of the second NAN cluster with aclock of the device, which is synchronized with the clock of the firstNAN cluster, to determine the TSF of the second NAN cluster.

According to aspects of the present disclosure, a station participatingin an NDL that initiates a move from a first NAN cluster to a second NANcluster may transmit NAN beacons in discovery windows (DWs) of thesecond NAN cluster. By transmitting NAN beacons, the device may enableother stations in the NDL to receive beacons of the second NAN cluster,as the other stations may not be able to receive beacons (e.g., due tochannel conditions) transmitted by a master device of the second networkcluster.

According to aspects of the present disclosure, a station participatingin an NDL that initiates a move from a first NAN cluster to a second NANcluster may determine times that a beacon or cluster transition messageannouncing the move may be transmitted and delay transmission of thebeacon or cluster transition message until one of the determined times.The station may determine the times based on one or more of a propertyof the NDL, a property of the station, an agreement with another stationreached during negotiation of the NDL, a property of the first NANcluster, or a value supplied by an application running on the station.

FIG. 10 illustrates example operations 1000 that may be performed by anapparatus (e.g., a station) participating in a network data linkcluster, according to aspects of the present disclosure. The operations1000 may be considered complementary to the operations 900 shown in FIG.9, in that they may be performed by an apparatus (e.g., a STA) that isparticipating in an NDL with another apparatus and receives informationindicating that the other apparatus is initiating a move from a firstnetwork cluster to a second network cluster.

Operations 1000 begin at 1002, where the apparatus obtains a first frameannouncing a move of a group of devices that includes the apparatus as amember, from a first network cluster to a second network cluster,wherein the first frame comprises timing information of a clockassociated with the second network cluster. For example and withreference to FIG. 8, node 808 obtains a frame including a beacon orcluster transition message announcing that the NDC 804 is to move to theNAN cluster 830 and including timing information of a clock of an anchormaster 832 of the NAN cluster 830. In the example, the frame may havebeen transmitted by node 812, as illustrated in FIG. 8.

At 1004, the apparatus determines, based on the timing information, adata communication window (DCW) timeline for the apparatus tocommunicate data with one or more members of the group after the move.Continuing the example above, node 808 determines a DCW timeline, basedon the timing information of the clock of the anchor master 832 of theNAN cluster 830, for the NDL 824.

At 1006, the apparatus communicates with the one or more members of thegroup after the move according to the DCW timeline. Continuing theexample above, node 808 communicates with node 816 via NDL 824 using theDCW timeline determined in 1004, above.

According to aspects of the present disclosure, the apparatus maygenerate and transmit a second frame including timing informationassociated with the second network cluster. The apparatus may alsoobtain an anchor master rank (AMR) value, included in the first frameannouncing the move, and include the AMR value in the second frame. Theapparatus may also include a time at which the apparatus will move to(e.g., transition to) the second network cluster and informationregarding the DCW timeline (e.g., an NDL schedule) in the second frame.

The apparatus may obtain a response to the second frame confirming theDCW timeline (e.g., an NDL schedule) from devices receiving the secondframe. That is, the apparatus (e.g., node 808 in FIG. 8) may wait tomove to the second network cluster (e.g., the apparatus may delaymoving) and begin using the determined DCW timeline until afterreceiving confirmation from other devices (e.g., node 816 in FIG. 8)that the other devices will use the determined DCW timeline.

According to aspects of the present disclosure, a station participatingin an NDL with a first NDL schedule (e.g., a DCW timeline) in a firstNAN cluster that has obtained a frame announcing a move to a second NANcluster may determine a second NDL schedule (e.g., a DCW timeline) foruse in communicating data with other members of the NDL cluster afterthe move to the second NAN cluster. The first NDL schedule may be basedon a sequence of DCWs beginning at the first offset relative to adiscovery window associated with the first NAN cluster. According tosome aspects of the present disclosure, the station may determine tomove to a second NAN cluster and determine the second NDL schedule to beused in the NDL cluster after moving to the second NAN cluster. Such astation may determine to use a second NDL schedule that comprises thesame base sequence of DCWs beginning at the first offset relative to adiscovery window associated with the second NAN cluster.

Additionally or alternatively, a first node (e.g., node 808 shown inFIG. 8) obtaining a frame announcing a move of an NDC from a firstnetwork cluster to a second network cluster may determine, based atleast on services available in the first network cluster and activity ofone or more NDLs, whether to veto the move. For example, the first nodemay determine that the first node desires access to one or moreservices, which are available on nodes of the first network cluster thatare not members of the NDC, more than the first node desires access toservices that are provided by other members of the NDC. In the example,the first node may then determine to veto the move, stay in the firstnetwork cluster, and transmit a message to a second node (e.g., a nodeannouncing the move) indicating that the first node will not participatein the move. In a second example, the first node may determine that anNDL has very high activity (e.g., a large amount of data is beingtransmitted via the NDL) and that the NDL should not be interrupted tobe moved to the second network cluster. Continuing the second example,the first node may then determine to veto the move, stay in the firstnetwork cluster, and transmit a message to a second node (e.g., a nodeannouncing the move) indicating that the first node will not participatein the move.

FIG. 11 illustrates example operations 1100 that may be performed by anapparatus (e.g., a station) participating in a network data linkcluster, according to aspects of the present disclosure. The operations1100 may be considered complementary to the operations 900 shown in FIG.9, in that they may be performed by an apparatus (e.g., a STA) that isparticipating in an NDL with another apparatus and receives informationindicating that the other apparatus is initiating a move from a firstnetwork cluster to a second network cluster.

Operations 1100 begin at 1102, where the apparatus (e.g., a node, a STA)obtains a first frame from a first device announcing a move of a groupof devices that includes the apparatus as a member, from a first networkcluster to a second network cluster, wherein the first frame comprisestiming information of a clock associated with the second networkcluster. For example and with reference to FIG. 8, node 808 obtains aframe from node 812 including a beacon or cluster transition messageannouncing that the NDC 804 is to move to the NAN cluster 830 andincluding timing information of a clock of an anchor master 832 of theNAN cluster 830.

At 1104, the apparatus determines, based on at least one of servicesavailable in the first network cluster or activity of a data link, toveto the move. Continuing the example above, node 808 determines thatnode 808 desires access to a service available from a node in NANcluster 802 that is not a member of NDC 804 (e.g., node 806) more thannode 808 desires access to any services provided by other members of NDC804.

At 1106, the apparatus generates a second frame indicating that theapparatus vetoes the move. Continuing the example above, node 808generates a second frame indicating that node 808 vetoes the move of NDC804 to NAN cluster 830.

At 1108, the apparatus transmits the second frame to the first device.Continuing the example above, node 808 transmits the second frame tonode 812.

An apparatus may be configured (e.g., programmed) to perform both ofoperations 1000 and 1100. For example, an apparatus may be a member ofan NDC and may receive a first frame from a first node announcing a moveof the NDC from a first network cluster to a second network cluster,wherein the first frame comprises timing information of a clockassociated with the second network cluster. In the example, theapparatus may desire access to a service provided by a second node inthe first network cluster and determine, based on services available inthe first network cluster, to veto the move and may transmit a secondframe to the first node indicating that the apparatus vetoes the move.Continuing the example, the apparatus may later receive a third framefrom the first node announcing a move of the NDC from the first clusterto a third network cluster, wherein the third frame comprises timinginformation of a clock associated with the third network cluster. In theexample, the apparatus may no longer desire access to the serviceprovided by the second node and may determine not to veto the move.Still in the example, the apparatus may determine, based on the timinginformation of the third network cluster, a DCW timeline for theapparatus to communicate data with one or members of the group after themove. In the example, the apparatus may communicate with the one ormembers of the group after the move according to the DCW timeline.

A first node that is in a first network cluster and has announced a moveof a group of network devices from the first network cluster to a secondnetwork cluster may obtain a frame from a second node that is a memberof the group indicating that the second node vetoes the move of thegroup to the second network cluster. According to aspects of the presentdisclosure, the first node may then determine whether to move to thesecond network cluster and possibly leave the group or to cancel themove to the second network cluster. For example and with reference toFIG. 8, node 812 may announce a move of NDC 804 to NAN cluster 830. Node814 may transmit a frame indicating that node 814 vetoes the move to NANcluster 830. Upon obtaining the frame, node 812 may determine whether tomove to NAN cluster 830 and possibly leave NDC 804 (and possibly breakNDL 822), or to cancel the move of NDC 804 to NAN cluster 830.

FIG. 12 illustrates a set 1200 of example communications timelines 1210,1220, 1230, 1240 within a first NAN cluster (e.g., NAN cluster 802 shownin FIG. 8), a second NAN cluster (e.g., NAN cluster 830 shown in FIG.8), and an NDL cluster (e.g., NDC 804, shown in FIG. 8), in accordancewith aspects of the present disclosure. The first NAN cluster has a NANdiscovery channel that is operated according to the exemplary timeline1210, with a NAN discovery window shown at 1212 and NAN beacons at 1214and 1216. The second NAN cluster has a NAN discovery channel that isoperated according to the exemplary timeline 1230, with a NAN discoverywindow shown at 1232 and NAN beacons at 1234 and 1236. The NDL clusteroperates on a channel according to an NDL schedule shown on theexemplary timeline 1220. The NDL schedule comprises two DCWs 1224, 1226.As illustrated, the DCWs begin an NDL offset 1222 after the beginning ofthe NAN discovery window 1212. Later, a member (e.g., node 812, shown inFIG. 8) of the NDL cluster detects a beacon from the second NAN clusterand determines to move to the second NAN cluster. As described above,the member may determine to use an NDL schedule 1240 with the same basesequence of DCWs 1244, 1246 at an offset 1242 relative to a discoverywindow 1232 associated with the second NAN cluster. Note that the offset1242 relative to the discovery window 1232 is of a same length as theoffset 1222 relative to the discovery window 1212.

According to aspects of the present disclosure, a station participatingin an NDL with a first NDL schedule in a first NAN cluster that hasinitiated a move to a second NAN cluster may determine a second NDLschedule (e.g., a DCW timeline) for use in communicating data with othermembers of the NDL cluster after the move to the second NAN cluster. Thefirst NDL schedule may have a first offset relative to a first clockassociated with the first NAN cluster. According to some aspects of thepresent disclosure, the station may determine the second NDL schedulesuch that the second NDL schedule has a second offset relative to asecond clock associated with the second NAN cluster, and set the secondoffset equal to the first offset, as illustrated in FIG. 12.

When a NAN Data Link (NDL) cluster is initialized, an NDL timeline maybe determined based on the discovery window timeline of the originatingcluster (e.g., the originating NAN cluster). Once the NDL cluster isinitialized, the NDL cluster may maintain a timeline that is independentof a discovery window timeline. According to aspects of the presentdisclosure, the NDL timeline may not shift, even as the originating NANcluster changes.

FIG. 13 illustrates a set 1300 of example communications timelines 1310,1320, 1330, 1340 within a first NAN cluster (e.g., NAN cluster 802 shownin FIG. 8), a second NAN cluster (e.g., NAN cluster 830 shown in FIG.8), and an NDL cluster (e.g., NDC 804, shown in FIG. 8), in accordancewith aspects of the present disclosure. As above, the first NAN clusterhas an exemplary NAN discovery channel timeline 1310, with a NANdiscovery window shown at 1312 and NAN beacons at 1314 and 1316. Also asabove, the second NAN cluster has an exemplary NAN discovery channeltimeline 1330, with a NAN discovery window shown at 1332 and NAN beaconsat 1334 and 1336. The NDL cluster operates on a channel according to anNDL schedule comprising DCWs 1324, 1326, as shown on the exemplarytimeline 1320. As above, the DCWs begin an NDL offset 1322 after thebeginning of the NAN discovery window. As described above, the NDLcluster may maintain an NDL timeline that is independent of a discoverywindow timeline. Thus, when a member (e.g., node 812, shown in FIG. 8)of the NDL cluster later detects a beacon from the second NAN clusterand determines to move to the second NAN cluster, the NDL cluster mayuse an NDL schedule 1340 with the same base sequence of DCWs 1344, 1346occurring at the same absolute times (as illustrated by the dashedlines) as the DCWs would occur on the exemplary timeline 1320, despitethat the sequence of DCWs is at an offset 1342 relative to the discoverywindow 1332 of the second NAN cluster that is different from the offset1322 to the discovery window 1312 of the first NAN cluster.

According to aspects of the present disclosure, a station may be amember of a first NAN cluster and may be participating in an NDL with anNDL schedule that has a first offset from a NAN discovery window of thefirst NAN cluster, according to a first clock associated with the firstNAN cluster. The station may initiate a move to a second NAN cluster, asdescribed above. The station may calculate a second offset, relative toa NAN discovery window of the second NAN cluster, of the NDL schedule.The station may calculate the second offset such that the NDL scheduleremains unchanged relative to the DCWs of the NDL schedule before thestation moved to the second NAN cluster, as illustrated in FIG. 13.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

In some cases, rather than actually transmitting a frame, a device mayhave an interface to output a frame for transmission. For example, aprocessor may output a frame, via a bus interface, to an RF front endfor transmission. Similarly, rather than actually receiving a frame, adevice may have an interface to obtain a frame received from anotherdevice. For example, a processor may obtain (or receive) a frame, via abus interface, from an RF front end for transmission.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. For example, operations 900 illustrated in FIG. 9correspond to means 900A illustrated in FIG. 9A, operations 1000illustrated in FIG. 10 correspond to means 1000A illustrated in FIG.10A, and operations 1100 illustrated in FIG. 11 correspond to means1100A illustrated in FIG. 11A.

For example, means for receiving, means for obtaining, and means forcommunicating may be a receiver (e.g., the receiver unit of transceiver254) and/or an antenna(s) 252 of the user terminal 120 illustrated inFIG. 2, the receiver (e.g., the receiver unit of transceiver 222) and/orantenna(s) 224 of access point 110 illustrated in FIG. 2, or thereceiver 312, antennas 316, and/or the bus system 322 illustrated inFIG. 3. Means for transmitting and means for outputting may be atransmitter (e.g., the transmitter unit of transceiver 254) and/or anantenna(s) 252 of the user terminal 120 illustrated in FIG. 2, thetransmitter (e.g., the transmitter unit of transceiver 222) and/orantenna(s) 224 of access point 110 illustrated in FIG. 2, or thetransmitter 310, antennas 316, and/or the bus system 322 illustrated inFIG. 3.

Means for placing, means for generating, means for including, means fordetermining, means for exiting, means for maintaining, means forsetting, means for delaying, means for waiting, and means for updatingmay comprise a processing system, which may include one or moreprocessors, such as the RX data processor 270, the TX data processor288, and/or the controller 280 of the user terminal 120 illustrated inFIG. 2 or the TX data processor 210, RX data processor 242, and/or thecontroller 230 of the access point 110 illustrated in FIG. 2.

According to certain aspects, such means may be implemented byprocessing systems configured to perform the corresponding functions byimplementing various algorithms (e.g., in hardware or by executingsoftware instructions) described above. For example, an algorithm fordetermining a data communication window (DCW) timeline for communicatingdata between a group of devices including the apparatus, and algorithmfor maintaining a local clock for the DCW timeline, and an algorithm forupdating the local clock based on at least one of a relative driftbetween the local clock and the clock associated with the first networkcluster, or a move of the apparatus from the first network cluster to asecond network cluster, may be implemented by processing systemsconfigured to perform the above functions.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For example, instructions for determining occurrence of a firsttype of discovery window for a network that occurs according to a firstinterval, instructions for determining occurrence of a second type ofdiscovery window for the that occurs according to a second intervalshorter than the first interval, instructions for obtaining, from atleast one other apparatus associated with the network, at least one oftime synchronization information or service information during at leastone of the first type of discovery window or the second type ofdiscovery window, and instructions for outputting, for transmission inthe network, at least one of the time synchronization information or theservice information during at least one of the first type of discoverywindow or the second type of discovery window.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is: 1-16. (canceled)
 17. An apparatus for wirelesscommunications, comprising: a receive interface configured to obtain afirst frame announcing a move of a group of devices that includes theapparatus, from a first network cluster to a second network cluster,wherein the first frame comprises timing information of a clockassociated with the second network cluster; and a processing systemconfigured to: determine, based on the timing information, a datacommunication window (DCW) timeline for the apparatus to communicatedata with one or more members of the group after the move, andcommunicate with the one or more members of the group after the moveaccording to the DCW timeline.
 18. The apparatus of claim 17, wherein:the processing system is configured to generate a second frameannouncing the move, the second frame comprising the timing informationof the clock associated with the second network cluster, and theapparatus comprises a transmit interface configured to output the secondframe for transmission.
 19. The apparatus of claim 17, wherein: theprocessing system is configured to generate a second frame announcingthe move, the second frame comprising information regarding the DCWtimeline, and the apparatus comprises a transmit interface configured tooutput the second frame for transmission.
 20. The apparatus of claim 19,wherein: the receive interface is further configured to obtain aresponse to the second frame confirming the DCW timeline; and theprocessing system is configured to communicate with the one or moremembers of the group according to the DCW timeline after the response isobtained.
 21. The apparatus of claim 17, wherein: the processing systemis further configured to determine a first offset, relative to adiscovery window (DW) associated with the first network cluster, ofanother DCW timeline used prior to the move; and the processing systemis configured to determine the DCW timeline based on the other DCWtimeline and a second offset relative to a DW associated with the secondnetwork cluster.
 22. The apparatus of claim 17, wherein: another DCWtimeline used prior to the move is based on a sequence of DCWs and afirst offset value; and the processing system is configured to determinethe DCW timeline based on the sequence and a second offset value. 23-38.(canceled)
 39. A method for wireless communications by an apparatus,comprising: obtaining a first frame announcing a move of a group ofdevices that includes the apparatus, from a first network cluster to asecond network cluster, wherein the first frame comprises timinginformation of a clock associated with the second network cluster;determining, based on the timing information, a data communicationwindow (DCW) timeline for the apparatus to communicate data with one ormore members of the group after the move, and communicating with the oneor more members of the group after the move according to the DCWtimeline.
 40. The method of claim 39, further comprising: generating asecond frame announcing the move, the second frame comprising the timinginformation of the clock associated with the second network cluster, andoutputting the second frame for transmission.
 41. The method of claim39, further comprising: generating a second frame announcing the move,the second frame comprising information regarding the DCW timeline, andoutputting the second frame for transmission.
 42. The method of claim41, further comprising: obtaining a response to the second frameconfirming the DCW timeline; and communicating with the one or moremembers of the group according to the DCW timeline after the response isobtained.
 43. The apparatus of claim 39, further comprising: determininga first offset, relative to a discovery window (DW) associated with thefirst network cluster, of another DCW timeline used prior to the move;and determining the DCW timeline based on the other DCW timeline and asecond offset relative to a DW associated with the second networkcluster.
 44. The method of claim 39, wherein: another DCW timeline usedprior to the move is based on a sequence of DCWs and a first offsetvalue; and the method further comprises determining the DCW timelinebased on the sequence and a second offset value. 45-69. (canceled)
 70. Awireless station, comprising: a receiver configured to receive a firstframe announcing a move of a group of devices that includes the wirelessstation, from a first network cluster to a second network cluster,wherein the first frame comprises timing information of a clockassociated with the second network cluster; and a processing systemconfigured to: determine, based on the timing information, a datacommunication window (DCW) timeline for the apparatus to communicatedata with one or more members of the group after the move, andcommunicate with the one or more members of the group after the moveaccording to the DCW timeline.